With Samba 4.8 and newer the lookup of a unknown SID returns NT_STATUS_INVALID_SID, here running again Samba AD 4.9.1: # rpcclient -c "lookupsids S-1-22-2-0" result was NT_STATUS_INVALID_SID The expected behavior is NT_STATUS_NONE_MAPPED, here running against Samba AD 4.7: # rpcclient -c "lookupsids S-1-22-2-0" S-1-22-2-0 *unknown*\*unknown* (8) Additional note: The NT_STATUS_INVALID_SID leads to a crash of the ACL editor of my Windows 7 version. So it seems to be very unexpected.
Additional additional note: Recently I've seen that the issue leads to a crash of the Windows 10 ACL editor, too.
May be a duplicate of bug 14213
(In reply to Roel van Meer from comment #2) Yes, thanks! Arvid reported the same bug there. I close this one, because the other report already contains more information. *** This bug has been marked as a duplicate of bug 14213 ***